This invention relates to airconditioning systems in general, and more particularly to airconditioning systems suited for residential use.
A single-fluid heating system is known in the prior art. One such system is described in Houbrecht's "Thermodynamique theorique," 2nd edition, 1972, pp 221-226.
Such a heating system is illustrated with regard to FIG. 1 and comprises a compressor 1 which draws used air at temperature t1 through an evacuation duct 2 from a residence L which requires heating. The temperature of this air is raised by quasi-adiabatic compression to a temperature t2 and forced through a conduit 3 into the high-temperature chamber 41 of a heat exchanger 4. In the high temperature chamber 41 it cools to a temperature t3 by giving up its heat to fresh air from the atmosphere A which is at an outside temperature t5. This fresh air is taken from the atmosphere A through a duct 6 and is made to circulate in the low-temperature chamber 42 of the heat exchanger 4 by a blower 11. The output rate of the blower 11 is equal to that of the compressor 1, so that the rate of flow of air through each chamber 41, 42 of the heat exchanger 4 is equal to that of the other. In the present context, the high-temperature chamber 41 of the heat exchanger 4 is the one in which the relatively hot fluid to be cooled is circulated, and the low-temperature chamber 42 is the one in which the relatively cold fluid to be heated is circulated.
The heated fresh air leaves the heat exchanger 4 and enters the residence L which is to be heated through a duct 7 and at a temperature t6 higher than temperature t1. The overall conditions relating to the heat exchanger 4 are such that t2-t6=t5. The used air from residence L is cooled to temperature t3 and then allowed to expand through a turbine 8 to deliver work. The air is then expelled into the atmosphere A through a duct 9 and at a temperature t4 less than outside temperature t5.
The turbine 8 is coupled to the compressor 1 and contributes to driving the compressor 1 together with a motor 10. The blower 11 may be made to rotate by a separate motor or by the motor 10 and/or the turbine 8.
FIG. 2 shows the successive states of the air circulating in the heating system illustrated in FIG. 1 as a function of coordinates t (temperature) and S (entropy). The used air removed from residence L at temperature t1 is subjected to adiabatic compression raising it to temperature t2 in compressor 1. This air arrives at the high temperature chamber 41 of the heat exchanger 4 where it is cooled from t2 to t3 and then allowed to expand through the turbine 8 to be expelled at temperature t4 into the atmosphere A, through the outlet conduit 9, where t4 is less than the outside temperature t5.
The fresh air taken in inlet conduit 6 from the atmosphere A at temperature t5 is raised to the required temperature t6 in the low temperature chamber 42 of exchanger 4 and then is injected at 7 into residence L at this temperature in order to provide the desired temperature.